This time-lapse video (one image every 30 seconds) shows a sponge contracting after sediment is added to the water it is filtering. These contractions work like a sneeze, helping remove sediment clogging the sponge’s filtration system.

University of Alberta researchers Danielle Ludeman and Sally Leys used a variety of drugs to elicit sneezes in freshwater sponges and observed the process using fluorescent dye—all recorded using time-lapse video. Their efforts focused on the sponge’s osculum, which controls water exiting the organism, including water expelled during a sneeze. Their research suggests the osculum is a sensory organ.

Leys said the discovery raises new questions about how sensory systems may have evolved in the sponge and other animals, including ones with nervous systems. It’s possible this sensory system is unique to the sponge, she said, evolving over the last 600 million years. Or it may be evidence of a common mechanism shared among all animals, and retained over evolutionary history.